The most commonly performed intra-ocular surgery is cataract extraction in which an opacified lens is removed. The natural lens is routinely replaced with an artificial implantable intra-ocular lens as is well known in the art. The cataract extraction surgery is usually performed on older adults.
With reference to FIG. 1, the normal drainage of fluid in an eye 10 is from the back (posterior 12) to front (anterior 14) chamber, with the line of demarcation between the chambers being the iris 16. The normal aqueous fluid of the eye is secreted by the ciliary body 18 located just behind the iris 16 and from there it passes forward through the pupil to reach the anterior chamber 14. Here the fluid is resorbed into ocular veins through special channels known as Schlemm's canals. This fluid flow is shown by the dashed arrow 20. After cataract extraction surgery, inflammation always occurs to some extent within the anterior chamber 14 of the eye 10. There is also the potential for intra-ocular infection.
To combat the inflammation and potential infection, anti-inflammatory and antibiotic eye drops are routinely used after cataract extraction, usually for a period of a month or longer. These eye drops initially require instillation 4 times per day, on average. The older adults on whom cataract extraction surgery is performed often have difficulty dispensing topical medications to themselves, frequently resulting in suboptimal dosing or need for an alternative topical medication delivery system sometimes achieved with assistance from another person.
In the vast majority of all patients undergoing cataract surgery, an opaque membrane forms on the back surface of the implanted artificial lens 22. This opaque membrane can form months to years following implantation of an intra-ocular lens 22. This opaque membrane develops because of growth and extension of cells from the periphery of the posterior capsule of the natural lens of the eye to the more posterior segment of that capsule. A posterior capsule that becomes thickened along the path of light rays passing through the pupil to the retina will degrade vision. The present day treatment for this opaque membrane problem is a second surgical procedure, typically performed with a YAG laser, to restore vision. This common practice adds significantly to the overall cost of visual rehabilitation for patients following cataract surgery.